In this work Nexar®-based nanocomposite membranes, consisting of tert-butyl styrene end blocks, hydrogenated isoprene inner blocks and a middle block that is selectively and randomly sulfonated, were prepared by dispersing bismuth oxide (Bi 2 O 3) nanoparticles inside. The aim was to evaluate their adsorption properties and photocatalytic activity. The chemical, structural and morphological properties of the produced materials were characterized by scanning electron microscopy (SEM), x-ray photoemission spectroscopy (XPS) and thermogravimetric analysis (TGA). We found that a partial reduction of Bi 2 O 3 to metallic Bi takes place during the nanocomposite preparation. The presence of the bismuth-based nanomaterials changes the light absorbance of the polymer affecting positively the dye removal ablity of the polymeric nanocomposite. The removal …